What is "idiocerus"

Idiocerus is a large genus of homopteran bugs belonging to the family Cicadellidae (the leafhoppers). The group is characterized by a very short and broadly rounded vertex (head); many species are very similar and difficult to identify. Most are found on specific host plants, particularly poplars and willows. For instance the common European species I. vitreus is found exclusively on certain poplars.